A number of publications are cited herein in order to more fully describe and disclose the invention and the state of the art to which the invention pertains. Each of these publications is incorporated herein by reference in its entirety into the present disclosure, to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.
Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise,” and variations such as “comprises” and “comprising,” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a pharmaceutical carrier” includes mixtures of two or more such carriers, and the like.
Ranges are often expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment.
This disclosure includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Chronic Inflammatory Disease
Inflammation is the immune response of tissues due to bodily injury. Acute inflammation is a normal, protective response that protects and heals the body following physical injury or infection, characterised by heat, swelling, and redness at the site of the injury. However, if inflammation persists for a prolonged period, it becomes chronic. Chronic inflammation is a hallmark of, and a contributing factor to, a range of disease conditions including rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, multiple sclerosis and psoriasis.
The inflammatory process is complex and involves a biological cascade of molecular and cellular signals that alter physiological responses. At the site of the injury, cells release molecular signals such as cytokines and interleukins that cause a number of changes in the affected area including dilation of blood vessels, increased blood flow, increased vascular permeability, invasion by leukocytes (white blood cells), and exudation of fluids containing proteins like immunoglobulins (antibodies). Several different types of leukocytes, including granulocytes, monocytes, and lymphocytes, are involved in the inflammatory cascade. However, chronic inflammation is primarily mediated by monocytes and long-lived macrophages; monocytes mature into macrophages once they leave the bloodstream and enter tissues. Macrophages engulf and digest microorganisms, foreign invaders, and senescent cells and macrophages release several different chemical mediators, including Tumour Necrosis Factor-alpha (TNFα), interleukins (e.g., IL-1, IL-6, IL-12 and IL-23) and prostaglandins that perpetuate the inflammatory response. At later stages, other cells, including lymphocytes, invade the affected tissues.
There is thus a common pathology underlying a wide variety of chronic inflammatory conditions. In addition, features of chronic inflammation are also observed in other diseases including cancer and metabolic diseases such as obesity and diabetes.
One of the most common chronic inflammatory conditions is rheumatoid arthritis (RA), a condition which affects up to 2% of the population worldwide. Although it is a complex disease, there are a number of physiological, cellular, and biochemical factors associated with the progression of RA that are common to a range of other diseases, including those with a component of autoimmunity (e.g., multiple sclerosis), inflammation (e.g., atherosclerosis and cancer), bone loss (e.g., osteoporosis) and proliferation (e.g., haematological malignancies). This makes the understanding of RA important not only for the study of a much broader range of diseases, but also suggests that pharmaceutical agents that work via modification of these common processes may have utility beyond RA. The latter is borne out by clinical practice where RA drugs have been shown to have broad utility across a variety of other conditions.
Rheumatoid Arthritis and Related Autoimmune/Inflammatory Diseases
Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic inflammation of the synovial lining of multiple joints coupled to progressive joint degradation. RA commonly affects the joints of the wrist and hands and may also affect the elbows, shoulders, hips, neck and knees leading to severe pain and disability (see, e.g., Scott et al., 2010). The World Health Organisation predicts that 23.7 million people suffer from RA, with incidence rising due to the association between the condition and increasing age.
The exact cause of RA, as for all the autoimmune disorders, remains unclear, although possible triggers include reduced self-tolerance, an abnormal response to environmental factors, infectious agents, and hormonal stimulus (see, e.g., Klareskog et al., 2006; Firestein et al., 2005).
At the cellular level, development of RA usually commences with T-cells infiltrating the synovial membrane lining the affected joint; this then leads to the activation of monocytes, macrophages and synovial fibroblasts by way of cell-cell contact and the subsequent release of various cytokines, including tumour necrosis factor-alpha (TNFα) and pro-inflammatory interleukins such as IL-1, IL-6, IL-12 and IL-23 (see, e.g., Astry et al., 2011). These pro-inflammatory cytokines are then instrumental in orchestrating several complex signal transduction cascades, including the NFκB, Interferon Regulatory Factor (IRF), Toll-like receptor (TLR), and Jak/STAT pathways (see, e.g., Malemud et al., 2010) which lead to the induction of genes coding for various products that propagate the inflammatory response and also promote tissue destruction. These products include tissue-degrading enzymes such as collagenases, matrix metalloproteinases (MMPs), cathepsins, and other pro-inflammatory factors such as selectins, integrins, leukotrienes, prostaglandins, chemokines, and other cytokines (see, e.g., McInnes et al., 2007; Smolen et al., 2003). In addition, these cells also increase the production of MMPs, leading to the degradation of the extra cellular matrix and loss of cartilage within the joint (see, e.g., Sun, 2010), a process that also involves a specialised class of cells known as osteoclasts and a factor known as Receptor Activator of Nuclear Factor Kappa-B Ligand (RANKL) (see, e.g., Takayanagi, 2009).
RANKL is an essential factor for the generation of osteoclasts, and upregulated RANKL-production leads to increased osteoclast differentiation and ultimately bone destruction (see, e.g., Long et al., 2012). The inflammatory response in RA leads to the accumulation of lymphocytes, dendritic cells, and macrophages, all operating locally to produce cytokines and other pro-inflammatory mediators such as TNFα and IL-6 which further potentiate the effects of RANKL on bone destruction. In addition, the inflammatory cascade leads to the hyperplasia of synoviocytes (see, e.g., Takayanagi, 2009), which in turn leads to the thickening and vascularisation of the synovium into a destructive and aggressive tissue known as a pannus. The pannus contains both osteoclasts, which destroy bone, and metalloproteinases, which are involved in the destruction of cartilage. As such, the RANKL axis is critical to the progression and pathology of RA as well as to the osteoimmune system (the interplay between the immune and bone systems), which is central to the pathology of a number of different disease conditions, described below.
The Role of TNFα in RA
The TNF superfamily of receptors and ligands plays a key role in the causation of inflammation and associated local and systemic bone loss. TNFα is a powerful pro-inflammatory agent that regulates many facets of macrophage function. It is rapidly released after trauma, infection, or exposure to bacterial-derived LPS and has been shown to be one of the most abundant early mediators in inflamed tissue. Among its various functions is its central role in orchestrating the production of a pro-inflammatory cytokine cascade. In addition to pro-inflammatory cytokines, TNFα also increases lipid signal transduction mediators such as prostaglandins. Based on these roles, TNFα has been proposed as a central player in inflammatory cell activation and recruitment and is suggested to play a critical role in the development of many chronic inflammatory diseases including rheumatoid arthritis (see, e.g., Liu, 2005; Feldmann et al., 2001; Brennan et al., 1996; Brennan et al., 1992). The importance of TNFα in RA is highlighted by the finding that antibodies blocking TNFα can prevent inflammation in animal models of RA, and that anti-TNFα therapy is currently the most effective treatment for RA (see, e.g., Pisetsky, 2012, and further detail provided below).
TNFα itself instigates a signalling cascade which leads to the activation of the transcription factors NFκB and AP-1 (see, e.g., Parameswaran et al., 2010). Binding of TNFα and IL-1 to their respective receptors leads to the recruitment of downstream signal transducers called TRAFs. Further kinases are recruited by the TRAFs, and the resulting kinase complex activates the MAP-kinase pathway, ultimately leading to activation of AP-1, and the phosphorylation of IκB kinase. IκB is the inhibitor of NFκB, which acts by preventing translocation of NFκB to the nucleus. Phosphorylation of IκB by IκB kinase leads to degradation of IκB. Once IκB has been degraded, NFκB migrates to the nucleus, where it promotes transcription of anti-apoptotic genes, which promote survival of T- and B-cells, thereby prolonging the immune response. This prolongation of the inflammatory response is central to the chronic nature of RA. The importance of NFκB activation is demonstrated by the fact that inhibition of NFκB activity by inhibitory peptides can prevent arthritis in animal models of RA (see, e.g., Jimi et al., 2004).
Other Key Factors in Rheumatoid Arthritis
As described above, a number of factors in addition to TNFα and NFκB act to promote inflammation in RA and other chronic inflammatory diseases. Amongst these are IL-6 and the Interferon Regulatory Factors (IRFs).
Interleukin-6 (IL-6) is a pro-inflammatory cytokine whose levels are increased upon activation of various immune system cells during inflammation in RA, predominantly macrophages and T cells. It has pleiotropic effects in disease via its key role in the acute phase response and is heavily involved in governing the transition from acute to chronic inflammation. It does this by modifying the composition of the white blood cell infiltrate in the inflammatory space, moving it from neutrophils to monocyte/macrophages (see, e.g., Gabay, 2006). In addition, IL-6 exerts stimulatory effects on T- and B-cells, thus favouring chronic inflammatory responses, as well as on osteoclasts, thus promoting the turnover of bone. These effects are involved in the pathology of a broad range of autoimmune/inflammatory diseases beyond RA, including systemic lupus erythematosus, atherosclerosis, psoriasis, psoriatic arthritis, asthma, chronic obstructive pulmonary disease (COPD), Sjogren's syndrome, atherosclerosis, and inflammatory bowel disease, as well as in cancers such as multiple myeloma and prostate cancer. In addition, IL-6 has been implicated in diseases involving bone loss (e.g., osteoporosis), diseases mediated by fibrosis (e.g., systemic sclerosis), diabetes, transplant rejection, various cancers (including, e.g., multiple myeloma, lymphoma, prostate cancer), neurodegenerative diseases (e.g., Alzheimer's), psychiatric disorders (e.g., depression), and certain rare vasculitides (e.g., Behçet's disease). For a full review, see, e.g., Rincon, 2012.
The interferon regulatory factors (IRFs) consist of a family of transcription factors with diverse functions in the transcriptional regulation of cellular responses in health and diseases. IRFs commonly contain a DNA-binding domain in the N-terminus, with most members also containing a C-terminal IRF-associated domain that mediates protein-protein interactions. Ten IRFs and several virus-encoded IRF homologs have been identified in mammals. IRFs are activated in response to endogenous and microbial stimuli during an immune response, and selectively and cooperatively modulate the expression of key cytokine and transcription factors involved in a variety of inflammatory processes. For example, stimulation of the receptor for bacterial lipopolysaccharide, TLR-4 activates a signalling cascade which activates both NFκB and IRF-5, whilst IRF-7 is activated by a process involving the STAT family of transcription factors, which are also, but independently, activated by IL-6.
The activation of the IRFs leads to a number of downstream effects including the specification of macrophage fate (see, e.g., Krausgruber et al., 2011), T helper cell differentiation (see, e.g., Zhang et al., 2012) and B-cell proliferation (see, e.g., Minamino et al., 2012). These diverse roles in disease are underlined by data from animal knockout models which show, for example, reduced levels of IL-6 and TNFα in response to inflammatory stimuli (see e.g., Takaoka et al., 2005).
In addition to the biological roles of the IRFs described above, several IRF family members have been genetically associated with predisposition to inflammatory conditions. For example, polymorphisms in IRF-3 and IRF-7 are associated with susceptibility to systemic lupus erythematosus (see, e.g., Akahoshi et al., 2008; Fu et al., 2011). In addition, IRF-5, which controls the fate of macrophages, is associated with susceptibility to RA, systemic lupus erythematosus, Wegener's Granulomatosis, Sjogren's syndrome, and systemic sclerosis (see, e.g., Sharif et al., 2012; Hu et al., 2011).
Treatment of Rheumatoid Arthritis
Early therapies for RA focussed on controlling the symptoms of the disease, mainly by reduction of inflammation, rather than retarding disease progression. These drugs included NSAIDs such as aspirin, diclofenac, and naproxen. Inflammation was further controlled by glucocorticoids, and their combination with NSAIDs provided reasonably effective short-term control of the inflammation. More recently, a more aggressive approach to treating RA has been introduced starting at disease onset, using so-called disease-modifying anti-rheumatic drugs (DMARDs), which act to slow or even prevent disease progression. These include a number of older drugs, including gold salts; sulfasalazine; antimalarials such as hydroxychloroquine; D-penicillamine; immunosuppressants such as mycophenolic acid, azathioprine, cyclosporine A, tacrolimus and sirolimus; minocycline; leflunomide; and most importantly, methotrexate (see, e.g., Smolen et al., 2003).
Methotrexate is now the gold-standard therapy for clinical trial comparisons, and is generally used in combination with newer therapies. It is effective in most patients but, in common with all of the above agents, has significant gastrointestinal side effects, which lead to roughly 50% of patients eventually having to cease treatment (see, e.g., Mount et al., 2005). A further drawback of these older DMARDs is the length of time taken for the drug to start acting, ranging from weeks with methotrexate, to months with gold salts. Whilst full remissions only occur in about a quarter of patients, for those showing no effect it is not generally possible to stop therapy without suffering the risk of a more violent disease rebound (see, e.g., Smolen et al., 2003).
In recent years, the treatment of RA has been revolutionised by the advent of biological agents which target specific inflammatory pathways. Several biological agents are currently approved for use in RA including anti-IL-6 and IL-1 biologics such as tocilizumab (Actemra®) and anakinra (Kineret®) (see, e.g., Scott et al., 2010). However, the first and most important of the biological agents are the anti-tumour necrosis factor (anti-TNF) therapies.
Anti-TNFα therapies are the market-leading treatment for RA. A variety of anti-TNFα agents are available including neutralising antibodies such as infliximab (Remicade®; J&J and Schering Plough) and adalimumab (Humira®; Abbott), or decoy receptors such as etanercept (Enbrel®; Amgen and Wyeth), both of which represent validated and highly effective treatments for RA as well as other diseases such as Crohn's disease and psoriasis. A number of other inflammatory and autoimmune disorders are also being investigated as potential targets. Other approaches to blocking the action of TNFα include the pegylated anti-TNFα fragment certolizumab (Cimzia®, UCB). All of these therapies act, ultimately, to prevent the activation of the downstream effectors of TNFα described above, including NFκB. However, in spite of their market success, the anti-TNFα therapies suffer from a number of side-effects including increased risk of certain malignancies such as lymphoma and serious infections such as Legionella and Listeria, as well as increased risk of heart failure, Hepatitis B reactivation, and demyelinating disease.
Finally, and most recently, a JAK kinase inhibitor, tofacitinib (Xeljanz®, Pfizer) has supplemented the range of RA treatments. However, tofacitinib suffers from a number of safety concerns including increased risk of serious infections as well as increased risk of gastrointestinal perforations, liver damage, and certain cancers, that are likely to limit its use in man (see, e.g., O'Shea et al., 2013).
As such, there remains a need for new and improved therapies for RA and other inflammatory diseases with a particular focus on improved safety.
The Osteoimmune System and Bone Disorders
The osteoimmune system is term for the combined and related interplay between the immune system and the skeletal system.
Under normal physiological conditions, the skeletal system provides support, mobility, protection for vital organs, and a mineral reservoir for calcium and phosphate. In order to achieve and adapt to these functions, the skeleton exists in a dynamic equilibrium characterized by continuous osteoclast-mediated bone resorption and osteoblast-mediated bone deposition (see, e.g., Karsenty et al., 2002). This biological process has been termed bone “remodelling” and occurs in coupled fashion with osteoblasts producing the key osteoclast differentiation factors, including RANKL, described above, and osteoclasts promoting bone formation by producing osteoblastic mediators as they degrade bone.
Both innate and adaptive immune cells exert effects on osteoclasts and osteoblasts through a variety of cell-surface and secreted mediators (see, e.g., Takayanagi, 2009). Activation of the RANKL receptor (RANK) on osteoclast precursors starts a cascade of transcriptional changes which results in the formation of osteoclasts and the expression of the machinery needed for bone resorption including molecules needed for attachment to bone, acid secretion, and proteolysis. Many of the transcription factors important for osteoclast differentiation are key regulators of immune responses, such as NFκB and nuclear factor of activated T cells c1 (NFATc1) and this process is also potentiated by factors involved in inflammation such as TNFα and IL-6.
In addition to its critical role in the progression and pathogenesis of RA, the osteoimmune system plays a critical role in a number of other diseases including osteoporosis and other bone disorders and cancer (see, e.g., Dallas et al., 2011).
Osteoporosis is a common disease characterised by reduced bone density, deterioration of bone tissue, and an increased risk of fracture. Many factors contribute to the pathogenesis of osteoporosis including poor diet, lack of exercise, smoking, and excessive alcohol intake. Osteoporosis also arises in association with inflammatory diseases such as rheumatoid arthritis, endocrine diseases such as thyrotoxicosis, and with certain drug treatments such as treatment with glucocorticoids. Indeed, osteoporosis-related fragility fractures represent one of the most important complications that may occur in patients with rheumatic diseases such as RA, systemic lupus erythematosus, and ankylosing spondylitis.
Paget's disease of bone is a common condition of unknown cause, characterised by increased bone turnover and disorganised bone remodelling, with areas of increased osteoclastic and osteoblast activity. Although Pagetic bone is often denser than normal, the abnormal architecture causes the bone to be mechanically weak, resulting in bone deformity and increased susceptibility to pathological fracture.
IL-6, TNFα, and RANKL signalling have been shown to play a major role in osteoclast over-activity and a consequent increase in bone loss (see, e.g., Tanaka et al., 2003; Roodman, 2006). The use of drugs which affect these pathways have been validated by the completion of clinical trials of the monoclonal antibody against RANKL, AMG-162 (Denosumab®, Amgen), for the treatment of osteoporosis/multiple myeloma, as well as by an increasing body of evidence that shows that the anti-TNFα and anti-IL-6 therapies also prevent bone loss in arthritic diseases (see, e.g., Ogata et al., 2012; Billau, 2010).
The Osteoimmune System and Cancer
Many types of cancer affect bone. Cancer-associated bone disease can be manifest by the occurrence of hypercalcaemia or the development of osteolytic and/or osteosclerotic metastases. Increased osteoclastic bone resorption plays a key role in the pathogenesis of both conditions. Whilst almost any cancer can be complicated by bone metastases, the most common sources are multiple myeloma, breast carcinoma, and prostate carcinoma. The most common tumours associated with hypercalcaemia are multiple myeloma, breast carcinoma, and lung carcinoma.
As described above, RANK/RANKL signalling is essential for osteoclast formation and bone resorption that occurs during skeletal remodelling. While physiological levels of RANK/RANKL signalling stimulate the proliferation and cell survival of mammary epithelial cells, aberrant RANK/RANKL signalling in these tissues has recently been shown to influence the onset and progression of breast tumorigenesis and blocking RANKL signalling using denosumab (Xgeva®, Amgen) has been shown to be an effective in preventing the secondary complications of bone metastases, such as pathologic fracture, and hypercalcaemia in patients with breast cancer (see, e.g., Steger et al., 2011).
Therapies that block RANK/RANKL signalling may also decrease the ability of osteotropic cancers to metastasize to bone. Signalling through RANK on the surface of human epithelial tumour cells as well as melanoma cells has been shown to induce a chemotactic response in these tumour cells whilst in a murine model of melanoma metastasis, therapeutic treatment of mice with osteoprotegrin, which neutralizes the RANKL receptor, RANK, significantly reduced tumour burden within the bones but not other organs.
In addition to a role for RANKL in cancer, there is growing evidence that activation of NFκB via molecules such as TNFα can play a major role in the promotion and progression of both haematological malignancies, such as myeloma and lymphomas, and solid tumours, such as breast, prostate, and lung cancer (see, e.g., Baud et al., 2009). There is also rising awareness of the role and importance of inflammation and the osteoimmune system in cancer and in the development of resistance to radiotherapy and to chemotherapeutic agents. Furthermore, it has been suggested that inflammation is in fact one of the basic hallmarks of cancer (see, e.g., Mantovani, 2009). Improving the efficacy of anti-cancer treatments by prevention of NFκB activation is therefore a promising strategy to augment existing therapeutic regimes and is currently under investigation, most notably for the treatment of multiple myeloma.
Defects in the normal apoptotic pathways are also implicated in the development and progression of tumour cell growth as well as in inflammation. Apoptosis (programmed cell death) plays a key role in the removal of abnormal cells; defects in the signalling cascades, which would normally lead to its induction, play a key role in oncogenesis. Radiotherapy and many chemotherapeutic agents act by causing cellular damage, which would normally induce apoptosis; defects in the pathway will therefore also reduce the effectiveness of such agents. The most important effector molecules in the signalling pathway leading to apoptosis are known as the caspases, which may be triggered by a number of stimuli, including TNFα binding to its receptor. Mutations in the genes which encode for the caspases have been found in a number of tumour types, including gastric, breast, renal cell, and cervical cancers as well as commonly in T-cell lymphoblastic lymphoma and basal cell ameloblastomas (see, e.g., Philchenkov et al., 2004). Compounds which activate caspases, and thus sensitise cells to apoptosis, would be highly effective as cancer therapies either as single agents or in enhancing the effectiveness of existing cancer chemotherapy and radiotherapy.
Agents that Prevent Inflammation Disrupt the Osteoimmune System
The inventors have identified new compounds which, for example, prevent inflammation and/or bone loss, and thus may be used in the treatment of diseases with an inflammatory or autoimmune component, including, for example, rheumatoid arthritis, inflammatory bowel disease, systemic lupus erythematosus, atherosclerosis, asthma, chronic obstructive pulmonary disease (COPD), uveitis, pelvic inflammatory disease, endometriosis, psoriasis and psoriatic arthritis; diseases which involve bone loss, including, for example, bone loss associated with rheumatoid arthritis, osteoporosis, Paget's disease of bone, and multiple myeloma; as well as cancer associated with activation of NFκB, with aberrant NFκB signalling, or with inflammation or IL-6 overproduction, including haematological malignancies such as multiple myeloma, leukaemia, T-cell lymphoblastic lymphoma, and other lymphomas (e.g., non-Hodgkin's Lymphoma), and solid tumours such as bladder cancer, breast cancer (female and/or male), colon cancer, kidney cancer, lung cancer, pancreatic cancer, prostate cancer, brain cancer, skin cancer, thyroid cancer, and melanoma; cancer associated with the inactivation or impairment of caspase-mediated cell death, such as gastric cancer, breast cancer, renal cancer, cervical cancer, and basal cell ameloblastomas; conditions associated with modulated activity of IRF-5 including Wegener's granulomatosis and systemic sclerosis; fibrosis associated with overproduction of IL-6, such as systemic sclerosis or scleroderma; neurodegenerative diseases associated with IL-6 overproduction, such as Alzheimer's disease; psychiatric disorders also associated with IL-6 overproduction, such as depression; diseases of angiogenesis associated with IL-6 overproduction such as age-related macular degeneration and diabetic retinopathy, IL-6 associated hyperplasias such as Castleman's disease and certain rare vasculitides associated with IL-6 overproduction, such as Behçet's disease.
Without wishing to be bound by any particular theory, the inventors believe that this action may be via a mechanism that involves blocking TNFα, and/or RANKL-signalling and/or IRF activity and/or inhibition of IL-6 production.
Known Compounds
Wang et al., 2010, describes certain compounds which apparently are high-affinity and selective dopamine D3 receptor full agonists. Examples of compounds shown therein include the following (see, e.g., pages 18-19 and 48-50 therein):

Chen et al., 2012 describes similar compounds.
Tsutsumi et al., 2005, describes certain compounds which apparently show DPP-IV inhibitory activity and apparently are useful in the treatment of type II diabetes and obesity. The following compound is shown as Example 89 on page 192 therein:

Hadida et al., 2007 describes certain compounds which allegedly are useful as modulators of ATP-binding cassette (“ABC”) transporters or fragments thereof, including Cystic Fibrosis Transmembrane Conductance Regulator (“CFTR”). The following compound is shown as Example 208 on page 77 therein:

Ralston et al., 2005, describes certain biphenyl-4-sulfonic amides for use: to inhibit osteoclast survival, formation, and/or activity; to inhibit conditions mediated by osteoclasts and/or characterised by bone resorption; in the treatment of bone disorders such as osteoporosis, rheumatoid arthritis, cancer associated bone disease, and Paget's disease; and in the treatment of conditions associated with inflammation or activation of the immune system. Examples of compounds shown therein include the following:

Greig et al., 2006, describes similar compounds.
Greig et al., 2008, describes certain biphenyl-4-sulfonic acid amides for the treatment of inflammation and/or joint destruction and/or bone loss; disorders mediated by excessive and/or inappropriate and/or prolonged activation of the immune system; inflammatory and autoimmune disorders, for example, rheumatoid arthritis, psoriasis, psoriatic arthritis, chronic obstructive pulmonary disease (COPD), atherosclerosis, inflammatory bowel disease, and ankylosing spondylitis; and disorders associated with bone loss, such as bone loss associated with excessive osteoclast activity in rheumatoid arthritis, osteoporosis, cancer associated bone disease, and Paget's disease. Examples of compounds shown therein include the following:

Greig et al., 2010b, describes certain biphenyl-4-sulfonic acid amides for the treatment of inflammation and/or joint destruction and/or bone loss; disorders mediated by excessive and/or inappropriate and/or prolonged activation of the immune system; inflammatory and autoimmune disorders, for example, rheumatoid arthritis, psoriasis, psoriatic arthritis, chronic obstructive pulmonary disease (COPD), atherosclerosis, inflammatory bowel disease, and ankylosing spondylitis; disorders associated with bone loss, such as bone loss associated with excessive osteoclast activity in rheumatoid arthritis, osteoporosis, cancer-associated bone disease, and Paget's disease; and cancer, such as a haematological malignancy and a solid tumour. Examples of compounds shown therein include the following:

Greig et al., 2013 describes similar compounds.
Greig et al., 2010a, describes certain biphenyl-4-sulfonic acid amides for the treatment of inflammation and/or joint destruction and/or bone loss; disorders mediated by excessive and/or inappropriate and/or prolonged activation of the immune system; inflammatory and autoimmune disorders, for example, rheumatoid arthritis, psoriasis, psoriatic arthritis, chronic obstructive pulmonary disease (COPD), atherosclerosis, inflammatory bowel disease, and ankylosing spondylitis; disorders associated with bone loss, such as bone loss associated with excessive osteoclast activity in rheumatoid arthritis, osteoporosis, cancer-associated bone disease, and Paget's disease; and cancer, such as a haematological malignancy and a solid tumour. Examples of compounds shown therein include the following:

New Compounds with Improved Properties
The HMC compounds described herein are protected against several toxic liabilities that are present in the known compounds, especially those shown in Greig et al., 2010a and show improved efficacy in models of disease.
Without wishing to be bound to any particular theory, the inventors believe that the particular combinations of substituents and their positions on the biaryl ring structure give rise to extraordinary properties. In addition to substantial improvements in acute in vivo toxicology, these combinations protect the compounds from general cytotoxicity, genotoxicity, and cardiovascular safety liabilities seen in the known compounds. Specifically, the HMC compounds described herein are negative for genotoxicity, show a substantial improvement in general cytotoxicity, and are substantially protected against inhibition of the human Ether-à-go-go related gene (hERG), which represents a major cardiovascular safety liability.
If a drug is to be used in the clinic, it must have a suitable safety and efficacy profile. It must show adequate acute safety to allow dosing to humans without the expectation of serious general side-effects. In addition, it must not cause genetic damage (genotoxicity) because agents that are genotoxic can act as carcinogens in humans. A clinically acceptable drug should also not inhibit hERG, an ion-channel which, when inhibited, can cause a fatal heart disorder known as long QT syndrome. Alongside these safety properties, the drug must be sufficiently potent against the biological target to give the desired therapeutic effect; it must have a sufficient solubility to be absorbed from the gastrointestinal tract; and it must have sufficient stability to remain in the circulation long enough to reach the biological target.
The HMC compounds described herein demonstrate improved efficacy in models of rheumatoid arthritis, for example, as compared with the compounds shown in Greig et al., 2010a. This is demonstrated both by a greater magnitude of effect on disease, as well as greater potency, both of which are seen, importantly, when the HMC compounds are administered when disease is already established. This mirrors the clinical setting for the use of these compounds. Moreover these effects are seen without overt toxicity.
The reduction of toxicological properties (adverse effects) of a drug is a developmental barrier of equal challenge and importance as compared to the optimization of pharmacodynamics (action of the drug on the body) and pharmacokinetic (action of the body on the drug) properties. The HMC compounds described herein provide substantial advantages as oral therapeutic agents (as compared to the known compounds) by improving acute general in vivo toxicology, genotoxic and cytotoxic safety, and cardiovascular safety, with little or no change in in vivo pharmacokinetics or loss of potency against the biological target.
The HMC compounds described herein combine the required characteristics of orally active agents for the treatment of, for example, chronic inflammatory conditions, bone loss, and cancer.